Substance abuse is a devastating disorder that affects millions of Americans. The economic and interpersonal impact of this disease is immense. Those who have faced early adversity are at increased risk for substance abuse, yet we know little about the mechanisms that contribute to this vulnerability. This research proposal, focused on adolescence, will characterize the development of brain systems involved in reward and decision-making processes. Despite dramatic behavioral changes and increased experimentation with drugs during childhood and adolescence, little is known the neurobiological correlates of substance use, abuse, and vulnerability during this time. Research in substance abusing populations indicates changes in decision-making and reward processing. The research proposed in this application is designed to illuminate more regarding these connections by examining how early adversity impacts reward and decision-making processes. Reward sensitivity and the ability to delay reward will be examined using functional magnetic resonance imaging. A modified gambling task will also be used to behaviorally probe decision-making in at-risk adolescents. Unique to this proposal, great effort has been focused on 1) controlling for potentially important neuropsychological differences and 2) defining risk more heterogeneously. By employing the Life-Stress Interview, a semi-structured interview, we aim to more accurately probe the subjective and objective aspects of early stress suffered. We hypothesize that early adversity, such as maltreatment or poverty, may affect important brain structures such as the prefrontal cortex and the nucleus accumbens, causing aberrant patterns in reward processing and decision-making. By using the tools of affective neuroscience and developmental psychopathology, we aim to uncover how early adversity may contribute to the vulnerability for substance abuse and inform the development of effective treatment programs for at-risk children. Epidemiological statistics indicate that nearly 13.5 million children and adolescents in the US face early adversity, such as extreme poverty or child maltreatment. Understanding the neurobiological vulnerability conveyed by these experiences is crucial to public health treatment and interventions. Those who have suffered stress early in development in addition tend to use and abuse more drugs and with greater frequency. Understanding these facets of vulnerability could have major impacts on public health prevention and intervention efforts. In addition, investigating vulnerability to substance abuse in at-risk samples could have unique insights on understanding the general developmental trajectory of substance abuse.